Compressor



WM J. G. ALDINGEW 2,63%,M

COMPRESSOR Filed May 29, 1935 2 Sheets-Sheet l attorneys 2, 993 wf-W M W M J. G. ALDIINGER COMPRESSOR 2 Sheeis-Shset 2 Filed May 29, 1935 3nventor Patented Apr. 7, 1936 UNITED STATES PATENT OFFICE aosaciv connssoa ration of Dela Application May 29, 1935, Serial No. 2.412%

ent application relates to an improvement on the structure of my prior application Serial 'No. 715,548, filed March 14, 1984, and an important feature of improvement, particularly for the larger size compressors, is the use of a separate distributing valve to control the difierential piston motor which actuates the unloading valve. In this way a single distributing valve can be used to operate simultaneously a plurality of unloading valves in a compressor having a plurality of working spaces and simultaneous rapid actuation of the various unloading valves can be assured.

Another advantage of the invention is that a single pilot valve, for example, an electrically actuated pilot valve, and a single distributing valve controlled thereby and in turn controlling the unloading valve motor, can be used. with any required number of cylinders, without change in their dimensions or capacity.

. A preferred embodiment of the invention will now be described in connection with the accompanying drawings, in which,--

Fig. l is a vertical sectional view transverse to the axis of the crank shaft. The planes of section are indicated by line l-l on Fig. 2.

Fig. 2 is an elevation of a two-cylinder com pressor with the invention applied.

Fig. 3 is a section through the pilot valve mechanism showing this in position to load the compressor.

Fig. 4 is a similar view showing the pilot valve in position to unload the compressor.

Referring first to Fig. 2, it will be observed that the two cylinders are formed in a single casting which includes the cylinders ii, there being a cored enlargement It encircling the upper portions of the cylinders aiid enclosing water jackets I3, and a cored enlargement [4 encircling the lower portions of the cylinders and enclosing an intake manifold l5. The suction connection indicated at I6 leads to the manifold l5. A series of intake ports H leads from the manifold I through the cylinder walls. The ports "are so located as to communicate with slots l8 dormed in the trunk piston it.

The trunk piston l9 carries the inlet valve N,

indicated as of the poppet type, and conforming to known practice. 22 indicates the usual safety head, there being a safety head mounted in each cylinder and heldin its lower or seated position by a coil compression spring 23 interposed between. it and the fixed cylinder head 24. The fixed cylinder head 24 is common to the two cylinders and encloses a. space 25 which is in communication with the compressor discharge connection, not shown.

The discharge valves it of the compressor are of the automatic type and are mounted within respective safety heads it as usual. An unloading passage t t formed in bosses ti on the main cylinder casting connects the intake manifold [15 with the unloading ports til. These are located in each cylinder wall at part stroke and their distance from the head end determines the degree of unloading efiected when the ports are open.

' A cylinder housing fill with head til is bolted to the main cylinder casting of the compressor, as indicatedin Fig. l, and receives and guides the unloading valve element, which takes the form of a combined diuerential piston and poppet valve. Formed in one piece are a relatively large piston head ti, a somewhat smaller trunk or body t2, and a valve head it coacting with the seat til. The seat ml is located to control how through the ports 2t and the flow is cut 0d when the valve member tit engages the seat The head'tl is provided with piston packing rings it of conventional form, and similar packing rings it are provided on the trunk portion 32.

A stem ill is threaded in the head til and may be turned by wheel it. A suitable packing gland is provided, as shown. When the stem ill is screwed in it forces the valve tt against the seat at, holding the unloading valve in its closed position. Under normal conditions, however, the

stem 3i! is in its outer position, as shown in Fig. 1,

leaving the unloading valve free to make its opening excursion.

Mounted on the side of the compressor is the body H of the distributing valve. A convenient way of mounting it is to support it on the pipe connection 42 which connects the interior of the housing M with the intake manifold 15. The housing ti is bored axially to provide a seat for a balanced piston valve having two valve heads 43 and Mt. The supply port 45 always communicates with the space within the valve chamber between the heads 43 and 4t. Pressure fluid taken from the discharge space 25 within the head structure 24 is conducted by the pipe t6 and filter 41 to the port 45. The pipe 42 which is at suction pressure communicates directly with the space above the upper valve head it and communicates by way of port 48 with the space below the lower head 43. Consequently the ends of the piston valve are both exposed to suction pressure and the valve is perfectly balanced.

Formed through the housing 4| are connections 5| and 52 which lead to ports in the valve chamber controlled by the valve heads 43 and 44. When the piston valve is in its upper position (see Fig. 3) the ports 52 are connected to the supply port 45 and the ports 5| areconnected by way of passage 48 and pipe 42 with'the suction manifold I 5. When. the piston valve is in its lowermost position (Fig. 4) the supply connection 45 is connected with the ports 5| and the ports 52 are connected by way of pipe 42 with the suction manifold I5.

The connections 5| communicate by way of branch pipes 53 with the ports 54 which lead to the small annular working spaces surrounding the trunks 32 of the unloading valves, it being understood, as indicated in Fig. 2, that there is an unloading valve for each cylinder of a multicylinder compressor.

Leading from each of the ports 52 is a pipe 55 which leads to a port 56. The port 56 communicates with the working space at the outer end of the corresponding unloading valve, that is, the space on the outer side of the piston head 3|. The balanced piston valve is urged in an upward direction by a coil compression spring 51 and may be forced downward against the urge of that spring by a piston 58 larger than the piston valve and working in a cylinder formed in the upper end of the housing 4|. This piston is provided with a bleed port 59 and the lower face of the piston 58 is subject to compressor suction pressure, that is pressure in the manifold I5 because of the direct connection afforded by the pipe 42.

The lower end of the housing 4| is enclosed by a cap 6| which also offers a seat for the spring 51. Theupper end of the housing 4| is closed by a cap 62 which contains a small chamber 63 supplied with pressure fluid at the discharge pressure of the compressor by a branch passage 64 leading from the passage 45. A pin valve coacting with a seat 66 controls flow from the chamber 63 to the space above the piston 58. The valve 65 is normally closed but may be opened by the excitation of a winding indicated by the numeral 61 applied to its enclosing casing. The terminals of the winding are indicated at 68 and 69 and the circuit through the winding may be controlled by any means, not shown, preferably a switch responsive to some physical condition affected by the operation of the compressor, for example, pressure in a receiver fed by the pressure, suction pressure, or where the compressor is included in a refrigerating circuit, the temperature created by the operation of the system.

It is important to observe that the capacity of the port through the seat 66 exceeds the capacity of the bleed port 59.

Operation When the pin valve 65 closes against seat 66 the port 59 will cause equalization of pressures above and below the piston 58, and the spring 51 will shift the balanced piston valve to its uppermost position (see Figs. 1 and 3). Under'these conditions fluid compressed by the compressor flows by way of pipe 46, filter 41, port 45, ports 52, pipes 55 and ports 56 to the working spaces at the outer sides of the large piston heads 3| of the unloader valves. Consequently the unloader valves close, as shown, and each piston IQ of the compressor is effective throughout its entire stroke. The closing movement of the unloader valve is facilitated by reason of the factthat the small annular working space to the right of the head 3| is exhausted by way of port 54, pipe 53, ports 5|, passage 43 and pipe 42 to the suction manifold l5 of the compressor.

If the winding 61 be excited the valve 35 will be lifted from the seat 66, admitting pressure fluid at the pressure of compressor discharge, by way of pipe 46, filter 41, passage 64, through valve seat 66, against the upper side of piston 53. Since the pressure fluid is supplied at a rate in excess of the vent capacity of port 59 the piston 53 will be forced downward, shifting the piston valve to its lowermost position (Fig. 4) the-space on the outer or left hand side of piston 3| is vented to the suction connection, while the annular space to the right of the piston head 3| is subject to discharge pressure. Consequently, the unloading valve is held in its outer or open position and the compressor piston I3 is ineffective until it has overtraveled the ports 28, because until it overtravels these ports the working space is connected by way of ports 28 and passage 26 with the intake passage 5 of the compressor.

It should be observed that a single winding 61 and a single piston valve actuated thereby control a plurality of unloading valves in unison. A standardized winding and a standardized piston valve can be used with compressors of various sizes and compressors having various numbers of cylinders. Furthermore the shifting of the unloading valves for the various cylinders will be simultaneous and the unloading valves will be held positively in their open and closed positions. It is important to observe that the effective area on the outer side of the piston 3| greatly exceeds the area of the end of valve 33 exposed to cylinder pressure.

While one specific embodiment of the invention has been described in considerable detail, the fact that various modifications are possible is fully recognized, and the scope of the invention is to be defined solely by the claims.

What is claimed is,-

1. The combination of a compressor having a working space; unloading means therefor; a reversible piston motor for shifting said unloading means between active and inactive positions; a. distributing valve shiftable to reverse said piston motor; a piston and opposed yielding means for shifting said distributing valve; and means for controlling the shifting of the last-named piston; said means comprising a valve and a. port of smaller flow capacity, one controlling the supply and the other discharge of pressure fluid to and from the last-named piston, and means for opening and closing the last-named valve.

2. The combination of a compressor having a. working space; unloading means therefor; a. reversible piston motor for shifting said unloading means between active and inactive positions; a distributing valve shiftable to reverse said piston motor; a piston and opposed yielding means for shifting said distributing valve; and means for controlling the shifting of the last-named piston, said means comprising a valve and a. port of smaller flow capacity, one controlling the supply and the other the discharge of pressure fluid taken' from the discharge of the compressor to and from the last-named piston, and means for opening and closing the last-named valve.

3. The combination of a compressor having a working space; an unloading valve therefor urged valve, the piston of said motor having a larger edective area in a closing than in an opening direction; a distributing valve shiftable to reverse said piston motor; a piston and opposed yielding means for shifting said distributing 1 valve; and means for controlling the shifting of iii the last-named piston, said means comprising a valve and a. port of smaller flow capacity, one controlling the supply and the other the discharge of pressure fluid taken from the discharge of the compressor to and from the last-named piston, and means for opening and closing the lastnamed valve.

d. The combination of a compressor having a working space; an unloading valve therefor urged in an opening direction by fluid pressure in the working space; a reversible differential piston motor for opening and closing said unloading valve, the piston of said motor having a larger effective area in a closing than in an opening direction; a distributing valve shiftable to reverse said piston motor; a piston and opposed yielding means for shifting said distributing valve; and means for controlling the shifting of the last-named piston, said means comprising a valve and a port of smaller flow capacity, one controlling the supply and the other the discharge of pressure fluid to and from the lastnamed piston, and means for opening and closing the last-named valve.

.5. The combination of a compressor having a plurality of working spaces; individual unloading means for corresponding working spaces; reversible piston motors, one for shifting each unloading means between active and inactive positions; a single distributing valve connected to reverse said piston motors in unison; a piston and opposed yielding means for shifting said distributing valve; and means for controlling the shitting of the last-named piston, said means comprising a valve and a. port of smaller capacity, one controlling the supply and the other discharge of pressure to and from the last-named piston, and means for opening and closing the last-named valve.

6. The combination of a compressor having a plurality of working spaces; independently operable unloading valves one for each working space, said valves being urged in an opening di rection by pressure in the corresponding working space; reversible differential piston motors each arranged to open and close a corresponding unloading valve, the pistons of such motors hav-- ing a larger effective area in a closing than in an opening direction; a single distributing valve connected to reverse said motors in unison; a. piston and opposed yielding means tor shifting said distributing valve; and means for controlling the shifting of the last-named piston, said. means comprising a valve and a port oi smaller capacity, one controlling the supply and the other discharge of pressure to and from. the last-named piston, and means for opening and closing the last-named valve.

l. The combination of an unloading device for a compressor or the like; a reversible doubleacting piston motor for shifting said device between loading and unloading positions; a balanced piston valve of the inlet and exhaust type for reversing said motor; yielding means urging said valve in one direction; a piston for forcing said valve in the opposite direction; and means for controlling the actuating pressure on the last-named piston, said means comprising a valve and a port of relatively smaller capacity,

. for controlling the actuating pres ur on the last-named piston, said means comprising avalve and a. port of relatively smaller capacity, one controlling supply and the other-discharge of pressure fluid, and electrically actuated means for opening and closing the last-named valve.

9. The combination of a compressor having a working space; unloading means therefor; a reversible piston motbr for shifting said unloading means between active and inactive positions; or distributing valve shiitable to reverse said piston motor; a. piston and opposed yielding means for shifting said distributing valve; and electrically controlled means for establishing and exhausting an operating pressure on the last-named piston.

lb. The combination oi a compressor having a 1 working space; unloading means therefor; a reversible piston motor for shifting said unloading means between active and inactive positions; a distributing valve shiitable to reverse said pis ton motor; a piston and opposed yielding means for shifting said distributing valve; and means for alternatively subjecting the last-named piston to pressure derived from the compressor discharge, and to compressor suction pressure.

ii. The combination of a compressor having a working space; an unloading valve therefor urged in an opening direction by fluid pressure in the working space; a reversible difierential piston motor for opening and closing said unloading valve, the piston of said motor having a larger effective area in a closing than in an opening direction; a distributing valve shiit'able to reverse said piston motor; a piston and opposed yielding means for shifting said distributing valve; and means for alternatively subjecting the lastnamed piston to pressure derived from the compressor discharge, and to compressor suction pressure.

l2. The combination of a compressor having a working space; an unloading valve therefor urged in an opening direction by fluid pressure in the working space; a reversible differential piston motor for opening and closing said unloading valve, the piston of said motor having a larger effective area in a closing than in an opening direction; a distributing valve of the balanced piston type shiitable to reverse said piston motor; and fluid pressure operated means for shifting said distributing valve.

13. The combination of a compressor having a plurality of working spaces; independently operable unloading valves one for each workin space, said valves being urged in an opening direction by pressure in the corresponding workerable unloading valves one for each working an opening direction; a single distributing valve connected to reverse said motors in unison; a piston and opposed yielding means for shitting said distributing valve; and means for alternately establishing and dissipating an operating prea- 5 sure on the last-named piston.

JACOB G. ALDJNGER. 

